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Aug. 10 1926. 1,595,346

L. F. LONG El AL PROCESS OF CORRUGATING SHEETS Filed Dec. 15. 1920 T Q P5 L ft 5 Fig.2.

INVENTORS ATTORNEY Patented Au 10, 1926.

UNITED STATES 1,595,346 PATENT OFFICE.

LEONARD F. LONG, OF HOBOKEN, NEW JERSEY, AND WALTER A. FORMAN, .OFBROOK- LYN, NEW YORK, ASSIGNORS TO THE BARRETT COMPANY, A CORPORATIONOI" NEW JERSEY.

PROCESS OF CORRUGATING SHEETS.

Application filed December 15, 1920. Serial No. 430,820.

This invention relates to a method for corrugating sheets of materialswhich would ordinarily be cracked or injured by bending or distortingthe same.

Heretofore processes have been known by which sheets of fibrous materialcan be made on a paper-making machine and duringthe process offormationof such sheets comminuted particles of waterproofin material can beembodied in said sheets by-merely introducing the same into thepaper-making machine along with thewatery pulp of H- brous materiaL.These sheets may be dried sheet is first formed from a plurality ofcon-- volutions or laminations of a single sheet that is formed on apaper-making machine, preferably in such a manner that the fibers alongcontacting surfaces of the convolutions or laminations are felted ormatted to an appreciable extent so as to roduce an initial integrationor joining of t e sheets. After the thick-sheet has been made it" isheated sufliciently to melt the contained watergroofl mg material and iscorrugated whi the waterproofing material is in this molten condition,the sheet being maintained in its corrugated shape until the same hasbeen cooled, thereby causing it to set and assumev a permanentcorrugated form.

The invention will be understood from the description taken inconnection'with the accompanying drawings in which Fig. 1 is somewhatdiagrammatic 'view showing how the sheet is formed on a papermakingmachine and rolled up.

Fig. 2 shows the sheet folded up. Fig. 3 is an elevation of a press inwhich the sheets may be corrugated.

In the drawings, reference character -1 refers to the vat of apaper-making machine in which is a foraminous cylinder 2, upon which asheet 3 of fibrous material is made in the usual way and picked up bythe wet blanket 4 passing over rolls 5 and 6. The sheet 3 passes betweenthe rolls 6 and 7 where some of the water is squeezed outand is thenrolled up on amandrel 8. The comminuted bituminous material isintroduced into the vatl along with the paper pulp and becomesincorporated in the sheet 3 as the same is formed. When a sufiicientnumber of turns have been made on the mandrel 8 the sheet is severed andthe roll is slit along a line parallel to its axis and then spread outas a flat sheet.

Instead of rolling the sheet up, as indicated in Fig. l, the sheet maybe folded back and forth, as indicated'in Fig. 2, thus forming a sheetof the desired numberof layers to produce the proper thickness. It ispreferable to have the sheet 3, as it isbeing rolled or folded-up asabove indicated, u1te wet so that the fibers on' the surfaces 0 the samewill become matted or felted. to an appreciable extent during the, inoperation.

he press shown in Fig. 3 consists of a base 9 and a member 10, both ofwhich are provided with hollow portions 11 and 12 into which may beintroduced heatmgand cooling fluids. 'The faces of the base 9 and member10'are corrugated as indicated, and

along the face of corrugations are disposed thin flexible plates 13preferabl of metal that are'heldby s rings 14 as in icated.

Heretofore 'it has been found that when thick sheets, say aboutone-quarter of an inch thick, are made of fibrous material and a highpercentage, say about to-90%, of comminuted bituminous material and arebent, they will crack or be injured on the surface or even break throughthe sheet. 'It

rqlling or fold has been found that sheets made as indicated in Figs. 1or 2 can be successfully corrugated by properly handling the same insuch a press as is indicated in Fig. 3. For this purposethe sheet isplaced between the thin metal plates 13 and after bringing the plates 13into contact with the surfaces ofv the sheet the same is thoroughlyheated 'by admitting heating fluid to the hollowportions 11 and 12 untilthe waterproofing material is melted. .This melting of the waterproofingmaterial decreases the stiffness or in contact with the surfaces of thesheet to be pressed, help to conduct the heat to said sheet anduniformly heat the same! These plates 13 also remain in close contactwith the surfaces of the sheet to be pressed and slide over'thecorrugated surfaces so that the sheet of fibrous and comminuted materialis thereby bodily carriedint'o the corrugations of the plates withoutbeing torn or stretched.

Preferably the water is dried from the sheet before it is inserted inthe press, and the sheet maybe heated to melt the bituminous materialbefore it is introduced into the press, or the sheet may be partiallyheated and the heating operation completed .after being introduced inthe press, orthe heating operation may take place entirely in the press.X en the sheet has been pressed so as to orm the corrugations, thepressure is maintained while the heating fluid is turned ofi and coolingfluid is introduced to cool the press and sheet, thus permitting thewaterproofing material to solidify and insuring the maintenance of thecorrugated form when the pressure 1s removed. The amount of pressure mayvary from 100 pounds to 300 pounds per square inch more or less and thedensification of the pressed sheet may be approximately 50%, and thespecific gravityof the pressed corrugated sheet may be made to be aboutthe same as that of the bituminous material itself. I

hot pressing operation in a press having corrugated faces so as tocorrugate the same as above described.

For certain purposes we have found that the bituminous material to beused may, for example, be pitch of a ;melting point of about 250 F., andthe amount of pitch. may be by weight about to 90% of the water-freecontent of the final product. I claim: I v 1. The herein describedprocess, which comprises forming on a paper-making machine a sheetcontaining fibr'ous material and pitch, pre-heating said sheetsufliciently to melt said pitch, and pressing said sheet betweencorrugated plates without materially tearing the, fibers of the sheet.2. The herein described process, which comprises forming on apaper-making'machine a" sheet containing fibrous material and solidwaterproofing material, pre-heating said sheet sufiiciently to meltsaidwaterproofing material, pressing said sheet in opposite directionsfrom its normal plane between corrugated plates without materiallytearing the fibers of the sheet, and cooling said sheet whilemaintaining said pressure.

3. The herein described process, which comprises forming on apaper-making machine a sheet containing fibrous material and pitch,pre-lieating said sheet sufiiciently to melt said pitch, pressing saidsheet in opposite directions from its normal plane between corrugatedplates without materially tearing the fibers of the sheet, and coolingsaid sheet whilemaintaining said pressure. r

4. The herein described process, which comprises forming on apaper-making machine 'a sheet containing fibrous material and solidwaterproofing material, preheating said sheet sufiiciently to melt saidwaterproofing material, and corrugating said sheet by application ofpressure substantially perpendicular to its surface along lines upon itsopposite sides staggered with respect to each other without materiallytearing the fibers of the sheet. 5. .The herein described process, whichcomprises forming on a paper-making machine a sheet containing fibrousmaterial and solid waterproofing material, pre-heating said sheetsufiicientlyto melt said waterproofing material, corrugating said-sheetby application of pressure substantially perpendicular to its surfacealong lines upon its opposite sides staggered with respect .to eachother without materially tearing the fibers of the sheet and coolingsaid sheet while maintaining said corrugating pres-' sure.

I 6. The herein described process, which comprises forming asheetcontainingfibrous material and solid waterproofing material,

pre-heating said sheet sufficiently to meltsaid waterproofing material,and pressing said sheet between corrugated plates that have thinflexible plates disposed along the faces of saidcorrugations conformableto said corrugations when under pressure.

7. The herein described process, which comprises forming on apaper-making mach e' a sheet containing fibrous material a'nllsolidwaterproofing material, pre-heating said sheet sufiiciently tome'ltsaid waterproofing' material, flat pressing said sheet andsubsequently hot pressing said sheet between corrugated plates withoutmaterially tearing the fibers of the sheet.

'In testimony whereof we aflix our signatures.

LEONARD r. LONG. WALTER A; roam.

